This invention relates in general to network management and more specifically to reducing the number of requests that need to be sent to a device to learn the management information of the device.
Network management involves managing the network resources, in order to meet service-level objectives. A Network Management System (NMS) monitors and measures the performance of a network across local and wide-area links, and also the services running on that network. The NMS typically includes tools for gathering data of the network elements; tools for data storage, analysis and prediction; tools for the configuration and control of the network elements; and tools for performance and system-planning management.
The NMS has two primary elements: a manager and an agent. The manager is an interface through which a network administrator manages the network. An agent acts as an interface between the manager and an actual device being managed. Each device includes a set of variables. Each variable on a device is identified by the NMS with a unique entity called an Object Identifier (OID).
In a network, same OID can be available in many devices. A particular OID represents the same parameter in all the devices. If the parameter is applicable for a device, then the OID is supported. For example, let the OID 1.3.6.1.2.1.3.1.0 represent the number of TCP packets received by a device. Then, Router 1: 1.3.6.1.2.1.3.1.0 represents the number of TCP packets received by Router 1, and Router 2: 1.3.6.1.2.1.3.1.0 represents the number of TCP packets received by Router 2, so on and so forth.
Some examples of the devices that contain managed variables are bridges, hubs, routers and network servers. The variables include hardware, configuration parameters and performance statistics, which directly relate to the current operation of the device in question. For example, for a device such as RAM, the managed variables include free buffer space, total buffer space, RAM speed, percentage of buffer space being used, etc. Each managed variable is represented by an OID. The parameters characterizing these variables are arranged in a Management Information Base (MIB), which is a virtual information database.
Communication between the network manager and the agents, to access the variables, is enabled by a communication protocol such as the Simple Network Management Protocol (SNMP). SNMP is an application layer protocol that facilitates communication between a device and a network management application through the use of Protocol Data Units (PDUs). SNMP is used to communicate management information between the network management systems and the agents in the network elements.
The NMS sends in requests to the devices for management information by means of a Get Request or a Get Next Request PDU. Each device responds to the request with a Get Response PDU, or sends an unsolicited message of unusual events to the management application, with the help of a Trap PDU.
The conventional techniques allow only one OID to be learnt in a single Get Next Request. Therefore, if there are ‘N’ variables, i.e., ‘N’ OIDs are available in a device, then ‘N’ separate Get Next Requests need to be sent to the device. For example, if there are 20,200 supported OIDs on a device, the time taken will be 20,200*(2*μ), where ‘μ’ is the time taken for the SNMP query to reach the device. Consequently, the time required to learn the management information of a device increases with the added number of variables. Much time is wasted in transmitting and receiving queries. Currently, the transmitting time is high because the number of Get Next Request packets sent to the device is very high, since one request packet is sent for each OID.